Reverse circulation fluid operated pump system

ABSTRACT

A fluid operated pump system of the open type wherein a pump unit which includes a fluid operated pump is circulated into and out of a well through a relatively large production tubing. Operating fluid under pressure for actuating the fluid operated pump is delivered thereto through a smaller, parallel supply tubing, the production fluid and the spent operating fluid discharged by the pump flowing to the surface through the larger production tubing to minimize fluid friction. The pump unit is normally biased upwardly in its bottom hole housing by the operating fluid under pressure in the supply tubing acting on a downwardly facing area of the pump unit. During normal operation of the fluid operated pump, the pump unit is latched against upward movement, and the system includes means movable downwardly through the production tubing into engagement with the pump unit for unlatching the pump unit when removal thereof is desired. Thereupon, the pressure of the operating fluid in the supply tubing acting on the downwardly facing area of the pump unit displaces the pump unit upwardly through the production tubing.

United States Patent McArthur et al.

[54] REVERSE CIRCULATION FLUID OPERATED PUMP SYSTEM [72] Inventors: Ralph F. McArthur, Huntington Park; Melle F. Geurts, Los Angeles,

both of Calif.

[73] Assignee: Kobe, Inc., Huntington Park, Calif.

[22] Filed: Dec. 29, 1970 21 Appl. No.: 102,376

[52] US. Cl ..417/358 [51] Int. Cl ..F04b 47/10 [58] Field of Search ..417/358, 448, 449, 450, 391,

Primary ExaminerRobert M. Walker Att0rneyHarris, Kiech, Russell & Kern [451 Aug. 29, 1972 ABSTRACT A fluid operated pump system of the open type wherein a pump unit which includes a fluid operated pump is circulated into and out of a well through a relatively large production tubing. Operating fluid under pressure for actuating the fluid operated pump is delivered thereto through a smaller, parallel supply tubing, the production fluid and the spent operating fluid discharged by the pump flowing to the surface through the larger production tubing to minimize fluid friction. The pump unit is normally biased upwardly in its bottom hole housing by the operating fluid under pressure in the supply tubing acting on a downwardly facing area of the pump unit. During normal operation of the fluid operated pump, the pump unit is latched against upward movement, and the system includes means movable downwardly through the production tubing into engagement with the pump unit for unlatching the pump unit when removal thereof is desired. Thereupon, the pressure of the operating fluid in the supply tubing acting on the downwardly facing area of the pump unit displaces the pump unit upwardly through the production tubing.

4 Claims, 6 Drawing Figures PATENTEDMIGZSIHTZ 3.687573 sum 1 or 3 /N1/EA/ 70/25 RALPH E MCARTHUR, MELLE E 650275 BY THE/R ATTORNEYS HAM/6, A7501, B11555 & K52

PATENTEDauszemn sum 3 or 3 .SR YR ERUWL VAE E w cG w M .Ru

6 M 6 PL E I 5 F PM 6 a REVERSE CIRCULATION FLUID OPERATED PUMP SYSTEM BACKGROUND OF INVENTION The present invention relates in general to a fluid operated pump system of the type wherein a pump unit which includes a fluid operated pump is circulated into and out of its operating position in a well.

More particularly, the invention relates to an open system wherein the production fluid discharged by the pump and the spent operating fluid discharged thereby are mixed together and conducted to the surface through a common, production tubing. Operating fluid under pressure for actuating the fluid operated pump is delivered thereto through a parallel supply tubing.

Still more specifically, the present invention contemplates a fluid operated pump system of the foregoing character which is of the reverse circulation type, i.e., of the type wherein the pump unit is circulated into an out of the well through a production tubing which is relatively large, and wherein the operating fluid is delivered to the pump unit through a parallel supply tubing which is relatively small. Such a reverse circulation system has the advantage of minimizing fluid friction since the combined flow of production fluid and spent operating fluid is conducted to the surface through the larger production tubing, the smaller flow of operating fluid under pressure being conducted downwardly to the pump unit through the smaller supply tubing.

With such a reverse circulation system, the pump unit is run in by introducing fluid under pressure into the production tubing thereabove, and is circulated out by introducing fluid under pressure therebeneath through the supply tubing. Since the supply tubing contains operating fluid under high pressure during normal operation of the fluid operated pump when the pump unit is in its housing at the lower end of the production tubing, some means must be provided for preventing upward circulation of the pump unit through the production tubing during normal operation of the fluid operated pump.

EXEMPLARY PRIOR ART US. Pat. No. 2,869,470, granted Jan. 20, 1959 to Clarence J. Coberly, discloses one way of preventing unseating of the pump unit during normal operation of the fluid operated pump by operating fluid under pressure from the supply tubing.

More particularly, the pump unit of the Coberly patent is provided with a latch means for latching the pump unit in its operating position against the upward bias resulting from the application of the operating fluid under pressure in the supply tubing to the lower end of the pump unit. After the pump unit arrives in its operating position in the housing at the lower end of the production tubing, the latch means is set by gradually building up the operating fluid pressure in the supply tubing, frictional resistance being sufficient to prevent upward displacement of the pump unit before the latch means is set as long as the operating fluid pressure is increased slowly. When it is desired to circulate the pump unit out through the production tubing, the latch means is released by increasing the pressure in the production tubing.

The system of the foregoing Coberly patent has the advantage that the pump unit can be latched and unlatched hydraulically by selective pressure applications to the latch means, there being no necessity for circulating in any kind of a retrieving tool. Thus, a feature of this prior art system is the speed with which the pump unit can be circulated out and a replacement unit circulated in.

However, the prior art system under consideration has the disadvantage that malfunctioning of the hydraulically operable latch means may make it impossible to set or release the pump unit. If the pump unit cannot be latched in its operating position, it must be circulated out and repaired or replaced. On the other hand, if the latch means cannot be released, due to the effects of corrosion, sand accumulations, or the like, it may be necessary to pull the entire tubing system.

SUMMARY AND OBJECTS OF INVENTION With the foregoing as background, the primary object of the invention is to provide a fluid operated pump system of the open, reverse circulation type wherein the pump unit is provided with a very simple latch means which is positive in its action and which is unlikely to malfunction, either in being set, or in being unlatched.

More particularly, an important object of the invention is to provide a simple mechanically actuated latch means which is set automatically upon arrival of the pump unit in its operating position in its housing at the lower end of the production tubing.

Another important object is to provide a latch means which is capable of being unlatched mechanically and very simply by an unlatching tool capable of being circulated downwardly through the production tubing into engagement with the pump unit.

Thus, the present invention provides a means for latching and unlatching the pump unit which is positive in its action and unlikely to malfunction, even though circulating the unlatching tool it does tend to increase somewhat the over-all time required to remove and replace the pump unit. However, the reliability of the latching and unlatching system of the invention virtually eliminates any possibility of prolonged down time as the result of malfunctioning of the latch means, which is an important feature.

The foregoing objects, advantages, features and results of the present invention, together with various other objects, advantages, features and results thereof which will be evident to those skilled in the fluid operated pump art in the light of this disclosure, may be achieved with the exemplary embodiment of the invention illustrated in the accompanying drawings and described in detail hereinafter.

DESCRIPTION OF DRAWINGS In the drawings:

FIG. 1 is a semidiagrammatic vertical sectional view of a fluid operated pump system which embodies the invention;

FIG. 2 is a fragmentary vertical sectional view show ing the upper end of an actual fluid operated pump system which embodies the invention;

FIG. 3 is a horizontal sectional view taken as indicated by the arrowed line 3-3 of FIG. 2, the latter figure being taken as indicated by the irregular arrowed line 22 of the FIG. 3;

FIG. 4 is a downward continuation of FIG. 2;

FIG. 5 is a downward continuation of FIG. 4; and

FIG. 6 is a downward continuation of FIG. 5 and shows the lower end of the fluid operated pump system which embodies the invention.

DESCRIPTION OF EXEMPLARY EMBODIMENT OF INVENTION Referring particularly to FIG. 1 of the drawings, and also to FIGS. 2 to 6 thereof, the numeral 10 designates a casing which is set in a well and which is provided with perforations 12 through which fluid is admitted from a surrounding productive formation 14.

Suspended in the casing 10 in the usual manner are parallel production and supply tubings 16 and 18. Connected to the lower end of and supported by the production tubing 16 is a bottom hole assembly 20 which includes a housing 22 for a fluid operated pump unit 24. The housing 22 is aligned with the production tubing 16 and communicates with the lower end thereof. The production tubing 16 is of a size to permit the pump unit 24 to move therethrough between its operating position in the housing 22 and the surface in running the pump unit into or out of the well. When the pump unit 24 is in its operating position in the housing 22, a fluid operated pump 26 forming part thereof is actuated by operating fluid under pressure from the supply tubing 18 to discharge production fluid from the well and spent operating fluid into the production tubing 16, as will be described in more detail hereinafter.

It will be noted that the production tubing 16 is considerably larger than the supply tubing 18. With this construction, fluid friction is minimized since the relatively large production tubing 16 is available to handle the combined flow of production fluid and spent operating fluid discharged by the pump 26. The smaller supply tubing 18 is required to handle only the smaller downward flow of operating fluid under pressure for actuating the fluid operated pump 26.

The pump unit 24 includes, in addition to the pump 26, a packer mandrel 28 connected to the upper end of the pump and extending upwardly therefrom. The packer mandrel 28 includes a downwardly facing packer cup 30 on which the fluid used to circulate the pump unit 24 out of the well acts. The packer mandrel 28 is provided at its upper end with a latch means 32 of the invention which latches the pump unit 24 in its operating position in the housing 22 in a manner to be described hereinafter.

The fluid operated pump 26 and the portions of the bottom hole assembly 20 associated therewith are conventional Consequently, they will be described briefly herein only to the extent necessary for an understanding of the invention.

When the pump unit 24 is in its operating position in the bottom hole housing 22, a bottom plug 34 at the lower end of the pump 26 is seated in a standing valve 36 at the lower end of the bottom hole housing 22. The bottom plug 34 is provided with a downwardly facing annular area 38 on which the operating fluid under pressure acts to tend to displace the pump unit 24 upwardly when the pump 26 is in operation. The operating fluid under pressure in the supply tubing 18 is applied to the annular area 38 through a passage means designated generally by the numeral 40 in FIGS. 1, 2, 4, 5 and 6. When the pump 26 is in operation, the upward force resulting from the application of the operating fluid pressure to the annular area 38 through the passage means 40 is resisted by the latch means 32. However, when it is desired to circulate the pump unit 24 out of the well through the production tubing 16, the latch means 32 is released so that the operating fluid under pressure acting on the annular area 38 displaces the pump unit 24 upwardly into the production tubing 16. Thereafter, the operating fluid under pressure beneath the pump unit 24 is also applied to the packer cup 30 in circulating the pump unit out of the well.

Operating fluid under pressure for actuating the pump 26 enters the engine end of the pump through an operating fluid intake 42 communicating with the passage means 40 through a branch passage means 44, FIGS. 1 and 4. Spent operating fluid from the engine end of the pump 26 is discharged through an operating fluid exhaust 46 which communicates with the interior of the housing 22 above the pump and below the packer cup 30.

Fluid from the well enters the pump end of the fluid operated pump 26 through the standing valve 36 and the bottom plug 34. Such well fluid enters an annulus 48 around the pump end of the fluid operated pump 26 through a port means 50, as best shown in FIG. 1 of the drawings. The pump end of the fluid operated pump 26 is double acting in the particular construction illustrated and draws well fluid from the annulus 48 through either of two inlets 52. The pump end of the fluid operated pump 26 discharges production fluid through outlets 54, FIGS. 1, 5 and 6. The outlets 54 communicate with a production fluid passage means which is designated generally by the numeral 56 and which communicates at its upper end with the annulus around the packer mandrel 28 below the packer cup 30.

The production fluid and the spent operating fluid discharged into the annulus around the packer mandrel 28 between the fluid operated pump 26 and the packer cup 30 flow upwardly through the packer mandrel, which is tubular, into the lower end of the production tubing 16, as will be clear from FIGS. 1 and 2 of the drawings. The spent operating fluid and the production fluid enter the lower end of the tubular packer mandrel 28 through a port means 58, FIGS. 1 and 4.

Thus, when the pump unit 24 is latched in its operating position by the latch means 32, the operating fluid under pressure in the supply tubing 18 enters the engine end of the pump through the operating fluid intake 42 to actuate the pump, the spent operating fluid being discharged through the operating fluid exhaust 46. Simultaneously, well fluid enters the pump end of the fluid operated pump 26 through the standing valve 36, the bottom plug 34, the port means 50, the annulus 48 and the well fluid inlets 52. The production fluid discharged from the production fluid outlets 54 flows through the passage means 56 and mixes with the spent operating fluid in the annulus around the packer mandrel 28 below the packer cup 30. The mixture of spent operating fluid and production fluid enters the tubular packer mandrel through the port means 58 and flows upwardly therethrough into the production tubing 16 and thence upwardly to the surface.

When it is necessary to circulate the pump unit 24 out for repair or replacement, the latch means 32 is unlatched, whereupon the operating fluid under pressure in the supply tubing 18 acts on the annular area 38 at the lower end of the pump unit and displaces the pump unit upwardly. Thereafter, the operating fluid under pressure acts on the entire area of the pump unit to displace same upwardly through the production tubing 16 to the surface, the standing valve 36 closing to permit this and the packer cup 30 entering into substantially fluid tight engagement with the interior of the production tubing 16. Bypassing of the packer cup 30 through the tubular packer mandrel 28 when circulating the pump unit 24 out is prevented in a manner which will be described.

Turning now to a more detailed consideration of the latch means 32, the latch means is shown in its latched position in FIG. 2 of the drawings and is shown in FIG. 1 as having been released by an unlatching means or tool 60 which has been circulated downwardly through the production tubing 16.

The latch means 32 comprises circumferentially spaced, elongated latches 62 carried by and extending generally longitudinally of the tubular packer mandrel 28 adjacent its upper end, the latches being disposed in complementary slots 64 in the packer mandrel. The latches 62 are mounted on the packer mandrel 28 by pivots 66 located closer to the lower ends of the latches than the upper ends thereof so that gravity biases the upper ends of the latches radially outwardly into positions beneath a downwardly facing internal annular latching shoulder 68 in the bottom hole assembly 20 adjacent its upper end. Preferably, the upper ends of the latches 62 are also biased radially outwardly by suitable springs, not shown.

With the foregoing construction, when the pump unit 24 has been circulated downwardly into its operating position, wherein the bottom plug 34 is seated in the standing valve 36, the upper ends of the latches 62 automatically move radially outwardly into their latching positions under the annular latching shoulder 68. Consequently, when operating fluid under pressure is delivered to the supply tubing 18 to operate the pump 26, the latches 62 prevent upward displacement of the pump unit 24 under the influence of the operating fluid pressure applied to the downwardly facing annular area 38 at the lower end of the pump unit.

When it is desired to circulate the pump unit 24 out for repair or replacement, the unlatching tool 60 is circulated in by inserting it into the upper end of the production tubing 16 and then introducing fluid under pressure into the production tubing thereabove. The unlatching tool 60 includes a probe 70 which enters the upper end of the tubular packer mandrel 28 and engages the lower ends of the latches 62 to pivot the upper ends thereof radially inwardly out of engagement with the annular latching shoulder 68, as shown in FIG. 1 of the drawings. The probe 70 also plugs the tubular packer mandrel 28 to prevent fluid subsequently introduced beneath the pump unit 24 from bypassing the packer cup 30.

The unlatching tool 60 is also provided with springbiased latches 72 which snap over an annular bead 74, FIG. 2, at the upper end of the packer mandrel 28 to secure the unlatching tool 60 to the packer mandrel 28. The unlatching tool 60 further includes a downwardly facing packer cup 76 and is provided at its upper end with a nose 78 for engagement with a conventional pump catcher, not shown, at the well head.

Considering the operation of the unlatching tool 60, when it is desired to retrieve the pump unit 24, the unlatching tool is inserted into the upper end of the production tubing 16 and circulated downwardly by introducing fluid under pressure thereabove. The supply tubing 18, under such conditions, is connected to a suitable point of disposal for fluid displaced by the unlatching tool.

When the unlatching tool 60 reaches the upper end of the pump unit 24, the probe moves the latches 62 to their inoperative positions and plugs the packer mandrel 28. At the same time, the latches 72 secure the unlatching tool 60 to the upper end of the pump unit 24.

Thereafter, operating fluid under pressure is again delivered to the supply tubing 18 to displace the pump unit 24 and the unlatching tool 60 to the surface through the production tubing 16, the upper end of the latter being connected to a suitable point of disposal for displaced fluid.

After removal of the pump unit 24 and unlatching tool 60, a replacement pump unit can be circulated in.

Although an exemplary embodiment of the invention has been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims appearing hereinafter.

We claim as our invention:

1. In a fluid operated pump system, the combination of:

a. a supply tubing and a production tubing set in a well, said production tubing having a housing at the lower end thereof with which said supply tubing communicates;

b. a pump unit, including a fluid operated pump,

movable downwardly through said production tubing into said housing, said pump being operable in said housing by operating fluid under pressure supplied thereto through said supply tubing to pump fluid from the well into said production tubing, and

said pump unit having a downwardly facing area which is in communication with said supply tubing when said pump unit is in said housing so that said pump unit is biased upwardly in said housing by operating fluid under pressure in said supply tubc. latch means for latching said pump unit in said housing against upward movement therein;

. means movable downwardly through said production tubing into engagement with said pump unit for unlatching said latch means; and

e. whereby the pressure of operating fluid in said supply tubing acting on said downwardly facing area displaces said pump unit upwardly.

2. A fluid operated pump system as defined in claim 1 wherein said latch means includes:

said latches project when the upper ends thereof are positioned radially outwardly under said annular shoulder, and wherein said unlatching means includes a probe insertable into said tubular member and into engagement with the lower ends of said latches to displace same radially outwardly and thereby retract the upper ends of said latches from under said annular shoulder.

4. A fluid operated pump system as set forth in claim 1 including means for latching said unlatching means onto said pump unit. 

1. In a fluid operated pump system, the combination of: a. a supply tubing and a production tubing set in a well, said production tubing having a housing at the lower end thereof with which said supply tubing communicates; b. a pump unit, including a fluid operated pump, movable downwardly through said production tubing into said housing, said pump being operable in said housing by operating fluid under pressure supplied thereto through said supply tubing to pump fluid from the well into said production tubing, and said pump unit having a downwardly facing area which is in communication with said supply tubing when said pump unit is in said housing so that said pump unit is biased upwardly in said housing by operating fluid under pressure in said supply tubing; c. latch means for latching said pump unit in said housing against upward movement therein; d. means movable downwardly through said production tubing into engagement with said pump unit for unlatching said latch means; and e. whereby the pressure of operating fluid in said supply tubing acting on said downwardly facing area displaces said pump unit upwardly.
 2. A fluid operated pump system as defined in claim 1 wherein said latch means includes: a. a downwardly facing internal annular shoulder in said housing adjacent the upper end thereof; and b. latches carried by and extending generally longitudinally of said pump unit adjacent the upper end thereof and pivotally connected to said pump unit intermediate their ends for radially outward movement of the upper ends thereof under said annular shoulder.
 3. A fluid operated pump system according to claim 2 wherein said pump unit is provided at its upper end with a tubular member on which said latches are pivotally mounted and into which the lower ends of said latches project when the upper ends thereof are positioned radially outwardly under said annular shoulder, and wherein said unlatching means includes a probe insertable into said tubular member and into engagement with the lower ends of said latches to displace same radially outwardly and thereby retract the upper ends of said latches from under said annular shoulder.
 4. A fluid operated pump system as set forth in claim 1 including means for latching said unlatching means onto said pump unit. 